added support for mongoid 5.0

lib/database_cleaner/mongoid/truncation.rb

@@ -20,7 +20,7 @@ module DatabaseCleaner
           ::Mongoid.database
         end
 
-      else
+      elsif ::Mongoid::VERSION < '5'
 
         include ::DatabaseCleaner::Moped::TruncationBase
 
@@ -37,6 +37,38 @@ module DatabaseCleaner
             ::Mongoid.database
           end
         end
+
+      else
+
+        def clean
+          if @only
+            collections.each { |c| database[c].find.delete_many if @only.include?(c) }
+          else
+            collections.each { |c| database[c].find.delete_many unless @tables_to_exclude.include?(c) }
+          end
+          true
+        end
+
+        private
+
+        def collections
+          if db != :default
+            database.use(db)
+          end
+
+          database['system.namespaces'].find(:name => { '$not' => /\.system\.|\$/ }).to_a.map do |collection|
+            _, name = collection['name'].split('.', 2)
+            name
+          end
+        end
+
+        def database
+          if not(@db.nil? or @db == :default)
+            ::Mongoid::Clients.with_name(@db)
+          else
+            ::Mongoid::Clients.default
+          end
+        end
       end
     end
   end